X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlfaq6.pod;h=4e5ba50ee5167b880fa638aaaa732d1b3898c98e;hb=d672126634c5e568812ed35d4c8ea53a9a55ee4c;hp=be7e8ecc73f356df00edc0ff8b69259840b35e51;hpb=79a522f5cdee4eadc7ad3cf5d6c2c8b42e148e07;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlfaq6.pod b/pod/perlfaq6.pod index be7e8ec..4e5ba50 100644 --- a/pod/perlfaq6.pod +++ b/pod/perlfaq6.pod @@ -1,6 +1,6 @@ =head1 NAME -perlfaq6 - Regexes ($Revision: 1.4 $, $Date: 2001/11/09 08:06:04 $) +perlfaq6 - Regular Expressions ($Revision: 1.12 $, $Date: 2002/06/01 22:31:09 $) =head1 DESCRIPTION @@ -9,7 +9,7 @@ littered with answers involving regular expressions. For example, decoding a URL and checking whether something is a number are handled with regular expressions, but those answers are found elsewhere in this document (in L: ``How do I decode or create those %-encodings -on the web'' and L: ``How do I determine whether a scalar is +on the web'' and L: ``How do I determine whether a scalar is a number/whole/integer/float'', to be precise). =head2 How can I hope to use regular expressions without creating illegible and unmaintainable code? @@ -70,9 +70,9 @@ delimiter within the pattern: =head2 I'm having trouble matching over more than one line. What's wrong? -Either you don't have more than one line in the string you're looking at -(probably), or else you aren't using the correct modifier(s) on your -pattern (possibly). +Either you don't have more than one line in the string you're looking +at (probably), or else you aren't using the correct modifier(s) on +your pattern (possibly). There are many ways to get multiline data into a string. If you want it to happen automatically while reading input, you'll want to set $/ @@ -166,7 +166,7 @@ appear within a certain time. close FH; ## Get a read/write filehandle to it. - $fh = new FileHandle "+). =head2 What's wrong with using grep or map in a void context? -Both grep and map build a return list, regardless of their context. -This means you're making Perl go to the trouble of building up a -return list that you then just ignore. That's no way to treat a -programming language, you insensitive scoundrel! +The problem is that both grep and map build a return list, +regardless of the context. This means you're making Perl go +to the trouble of building a list that you then just throw away. +If the list is large, you waste both time and space. If your +intent is to iterate over the list then use a for loop for this +purpose. =head2 How can I match strings with multibyte characters? -This is hard, and there's no good way. Perl does not directly support -wide characters. It pretends that a byte and a character are -synonymous. The following set of approaches was offered by Jeffrey -Friedl, whose article in issue #5 of The Perl Journal talks about this -very matter. +Starting from Perl 5.6 Perl has had some level of multibyte character +support. Perl 5.8 or later is recommended. Supported multibyte +character repertoires include Unicode, and legacy encodings +through the Encode module. See L, L, +and L. + +If you are stuck with older Perls, you can do Unicode with the +C module, and character conversions using the +C and C modules. If you are using +Japanese encodings, you might try using the jperl 5.005_03. + +Finally, the following set of approaches was offered by Jeffrey +Friedl, whose article in issue #5 of The Perl Journal talks about +this very matter. Let's suppose you have some weird Martian encoding where pairs of ASCII uppercase letters encode single Martian letters (i.e. the two @@ -719,7 +730,7 @@ in L. =head1 AUTHOR AND COPYRIGHT -Copyright (c) 1997-1999 Tom Christiansen and Nathan Torkington. +Copyright (c) 1997-2002 Tom Christiansen and Nathan Torkington. All rights reserved. This documentation is free; you can redistribute it and/or modify it